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Mole percents

How do you convert from a mole percent to a mass percent?
Lets say I have 50mol% Benzene, how to I make it into a mass/weight%
Original post by HannahWilson9
How do you convert from a mole percent to a mass percent?
Lets say I have 50mol% Benzene, how to I make it into a mass/weight%

Multiply the mol percent by the relative mass and this gives you the proportion by mass of each element in the compound. Then change to percentage by 100 x mass/total mass.

Example Benzene :

50% (50/100) by mol carbon = 0.5 x 12 = 6 mass units
Hydrogen is 50% (50/100) by mol = 0.5 x 1 = 0.5 mass units

this gives you a ratio of 6 : 0.5 or 12:1

Hence percentage carbon = 100 x 12/13 = 92.3%
Hence percentage hydrogen = 100 x 1/13 = 7.7%
Original post by charco
Multiply the mol percent by the relative mass and this gives you the proportion by mass of each element in the compound. Then change to percentage by 100 x mass/total mass.

Example Benzene :

50% (50/100) by mol carbon = 0.5 x 12 = 6 mass units
Hydrogen is 50% (50/100) by mol = 0.5 x 1 = 0.5 mass units

this gives you a ratio of 6 : 0.5 or 12:1

Hence percentage carbon = 100 x 12/13 = 92.3%
Hence percentage hydrogen = 100 x 1/13 = 7.7%

Thank you. What if it is a mixture solution. The mixture is made up of benzene and ethane, both with 50mol%, so in this case, it's the benzene + ethane that makes up the 100%.
Do I just do:
Benzene = 0.5 x 78 = 39 mass units
Ethane = 0.5 x 30 = 15 mass units

so benzene = 72wt%
Ethane = 28wt%
(edited 3 years ago)
Original post by HannahWilson9
Thank you. What if it is a mixture solution. The mixture is made up of benzene and ethane, both with 50mol%, so in this case, it's the benzene + ethane that makes up the 100%.
Do I just do:
Benzene = 0.5 x 78 = 39 mass units
Ethane = 0.5 x 30 = 15 mass units

so benzene = 72wt%
Ethane = 28wt%


Works for me :smile:
Original post by charco
Works for me :smile:

Thank you, this helped me a lot

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